1. Field of the Invention
This invention relates generally to a remote control system for powering up and powering down electrically driven equipment and more particularly computer power equipment from a remote site utilizing standard communication lines to transmit the control and identification signals.
2. Description of the Prior Art
According to a conclusion of a million dollar study carried out for the Datron Corporation by Booz, Allen, and Hamilton, computers in the United States alone will transmit or receive 250 billion data transactions over telecommunication lines by the year 1980.
Computer systems are beginning to utilize the vast network of telecommunication links that span the industrialized countries of the world, carrying telephone, telegraph, and television signals. It is now practical for one computer to dial up another computer and transmit information. Typical devices for accomplishing this utilizing telephone lines are disclosed in U.S. Pat. Nos. 3,347,988 issued Oct. 17, 1967 and 3,631,395 issued Dec. 28, 1971.
However, in these typical prior art communication systems the computer systems remain in a powered-up condition regardless of whether or not the computer is receiving or transmitting information. Yet the bulk of computer communication is "off-line" wherein telecommunication data to be transmitted to a remote computer are first written onto magnetic tape or disk, or punched into paper tape or cards for later transmission to the remote computer during off-load hours. The transmission of the batch of data may take anywhere from a few minutes to a few hours and is generally done at night or weekends. Despite the fact that only a relatively short time is required for the actual transmission of data the computer power remains on all night or all weekend. In this day and age of power conservation, it is desirable to have a device for turning power on and off remotely so that power is being expended only during actual transmission of data.
There are a number of devices available in the prior art for performing various functions remotely. N. G. Duncan discloses a "Remote-Control System With Coded Audio Signals" in U.S. Pat. No. 3,384,713 issued May 21, 1968 wherein sound generator means are utilized to remotely control a terminal circuit. In U.S. Pat. No. 3,484,694 entitled "Data Transmission System Wherein System Control is Divided Between a Plurality of Levels for Remote Location Activation," A. Brothman, et al disclosed a data processing center having a quiescent operating state wherein all the remote locations of the system are sequentially sensed so as to transmit their readings back to the data processing center. Other typical remotely controlled systems are disclosed in the following U.S. Pat. Nos. (a) 3,384,713 issued May 21, 1968; (b) 3,705,385 issued Dec. 5, 1972. This list is not inclusive and there may be other similar remotely controlled data transmitting and receiving systems of which the applicant is not aware. Most of these devices are directed to controlling the reading of meters requiring fairly low power, audio signals, and/or more than one frequency for transmitting and receiving control signals, and in many instances are expensive to manufacture, install and maintain. What is needed is a simple, reliable low cost device, easy to install and easy to maintain that can distinguish as well when wrong numbers are called via the telephone transmission line.